The present invention relates to filling plastic bags with liquids and the like. More particularly, the present invention relates to a continuous high speed and low cost process for both forming and filling plastic bags.
The prior art is lacking in a method of liquid-filling plastic bags which is sufficiently fast and inexpensive to render it competitive with processes for filling bottles or cans. One of the major problems in this regard relates to the difficulty of gripping and holding open the bag during filling. In other words, the flimsiness of the plastic bag renders it unsuitable for high speed filling processes. In addition, it is important to avoid splattering the fill liquid onto an inside portion of the bag surface where a closure seal is to be made. Specifically, plastic film seals are usually made by heat and pressure. This may be done with heated bars, heated rollers, or with an ultrasonically-driven shoe which provides pressure and generates heat with high frequency hammering of the shoe against the plastic film which is positioned between the shoe and an anvil. In any of these sealing methods, certain liquids on either of the sealed surfaces tend to prevent proper sealing.
Still another problem related to high speed bag filling relates to spillage. Specifically, it is difficult to run a high speed process with an open-ended bag properly oriented to avoid spillage of the contained liquid. Sealing of the bag before such spillage occurs would appear to require quick movement of the open bag, and such movement itself would tend to cause spillage.
It is therefore an object of the present invention to provide a high speed, low cost process for filling plastic bags with liquid or liquid-like material.
It is another object of the present invention to provide a high speed method of bag filling in which the fill liquid cannot impair the bag closure seal.
Another object of the present invention is to provide a high speed process of liquid-filling plastic bags wherein spillage problems are avoided.